This invention relates to a process for producing a cooling channel piston, above all, for a diesel engine and a cooling channel piston produced according to said process.
This type of process is known from DE 44 46 726 A1. With the cooling channel piston known from this specification, a piston blank is produced, and an annular recess and the cooling channel, which is open towards the bottom, are inserted into the piston by means of metal cutting, and, subsequently, the outer contour of the piston is completed.
Further, the axial height of the annular recess at least matches that of the cooling channel. This is necessary, because, in order to produce a cooling channel that is open towards the bottom, a hook-shaped turning tool must be inserted into the recess, and the cooling channel must be machined in the desired shape as a result of corresponding axial and radial infeed actions. The height of the hook-shaped turning tool that is required to produce the cooling channel produces an overall height of the piston that is undesirable, since there is a trend to produce pistons that are shallower and shallower and, consequently, more compact combustion engines. In particular, because of the deep insertion of cooling channels into the piston head, the turning tool requires a channel height-increasing hook-shaped end which contributes to an undesired increase in the overall height of the piston. This means that the distance between the lower section of the piston head and the upper section of the of the piston skirt becomes undesirably high.
It is the object of the invention to avoid the above described disadvantages.
The inventive process is characterized in that the annular recess is supplemented by an additional recess by means of metal cutting and the production of the cooling channel is begun in an area parallel to a face of the piston boss. By means of these procedural steps, the overall height of the piston can be reduced, because the tool which forms the cooling channel has a greater overall height than the annular recess. By means of these procedural steps, the cooling channel can be produced in the usual manner with the required geometric configuration and with respect to the volume of cooling medium to be accommodated in which, at the same time, the overall height of the piston is clearly reduced as a result of reducing the height of the annular recess. The axial height of the annular recess is thus smaller than the axial height of the cooling channel.
The inventive process and the pistons produced in accordance therewith are described in the following by means of an embodiment and the drawing figures, with the invention not being restricted to the disclosed embodiment.